Railway signaling system



Oct.'21, 1930. s. w. BA UGH MAN RAiLWAY SIGNALING SYSTEM Filed July 27. 1:929

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Patented OctQZl, 193G 7 me a SWITCH & SIGLTAL COMPANY, PENNSYLVANIA- RAILWAY sIGiTiiLING sYS EM Application filed July 27,- 1929} Serial 1%; 381,468; I; I

My invention relates to railway signaling systems, and particularly to systems of thetype involving direct current track relays operated from alternating track circuits 5 through the medium of rectifiers; I One feature of my invention sion, in systems of this character, of means for preventing'false operation of trackrelays {in the event failure ofinsulated railjoints, and also false. operation of the track relay due to electric'propulsion current;- will describe one form of system embodying my invention, and will then point out the I novel features thereof in claims. matic view showing one formio f signaling systemembodying'my invention. if f j Referring to j the drawing-the reference .characters lfand 1 designate the track rails of a stretchof railway track, which Stretch.

is dividedby insulatedrail 'joints 2 'into a plurality of successive sections, suchas and B+G 'When the railway isiofthe electric propulsion type, i provicled w h 1 5 usual inductive bonds for conductingi pro-i jpulsion current aro'undthe insulated joints 2;

Each track section is provided with a source of alternating track circuit. current which,

" as herevshowni-sthe secondary of a trans-.

former designated by the 'referencecharacter T with an exponent correspondingto the location. The frequency ofrthe track cir cuit'current supplied to each sectionis :difler-"j ent from the frequency'suppliecl to: each of 'suthe' adjoining sections,' and as here shown;

one section is supplied] with 'traclrcirc'uit current of cycles'persecond-and the adjacent one with cycles per second Thetwo frequencies may be "supplied to the primaries f -ifi'of the transformersT'in any's'uitable manne'r, suclnforexample; as by 'twoseparate;

transmission lines or by local vibration generators of alternatingcurrentl Asis'hown in] T the drawing, however," the ;60 cycle] current is -15 supplieddirectly from av'transmission line"L;

is the provi- The accompanying" drawmg 1s a diagramthe filter elementsis notr essentialil or'sw'issvnrn;rEnNsYLVAmA; A conroaer ofn or Y whereas the 120 current supnlied from .thissame transmission line through afull-x waverecufierH 1 That is lto say, the' primarrie sof transformers T and fr are connected *cli-rectlywith the transmission line Lyw hich is constantly furnished with '60 cycle current-1" by a generator Gr, whereas theprimary of transformer T is connected with the'o'ut'put i Y terminals of a full wave rectifier H the-input V Y I terminals ofj whichlare "connected with the I transmission lineL; It follows that 120 cycle 7 current is deliveredito thetrackrails" ofsec- I 1 Each track 's'ection is provided *withxga'i transformerdesignated the 'refer'enCe'Q QQ character D with an exponent-corresponding 1 to the location, the primary of whichiscon f Y necte'd-"across the' railsjofthe section. f'I he: secondary"off each transformer-D supplies track circuit currentto'a ectifier E and rent type. inter osedaloetween" each 'trans= I qiiencyiof the track circuitjcurrent supplied *t-his rectifier inlturn supplies unidirectional; V {cirrrenttd'atrack 'relayR,offthexdirect cur- ,f onn erD and-the, ssociated ectifie 'E is'Ea filter designated by the 1referencei character 78 0 ivF 'wi'th an exponentcorresponding t'oj'the to o location; Eachffiltenis tuned to"the=fre- 1 tltlie ifails of-the associated sections/Each; I

this specific structure and, arrangement fiat thes filters as51 m;sho n;comprises a l- I v condense land anauto-transformerfallout v f It willbe'not'ed-that when-agiven sectioni f I ,is'unoccupiecl,the associatedtrack relay R T" "will, he energized hecause the filter Qa'ssov s ci'atedwithsuchjlsectionfreely transmits the 5:; track circuit current sup'plied' to the section. I 7 *lij will assume, however,;that}the' insulated oints 2' at the point B; break down; thereby allowing alternating current-1 tramp-t ns 1 f: former 1T to be supplied o to"transformrf,

'D J; This currentis, of, 120 cycles whereas the {filterl F yis tuned to 60fcy'cles;withgthe resultjprthat the} current from' transformer i109 1 a-ninsulatedflrailjointshould failthe relay for one ofthe affected: sectionswill. not be falsely operated: by track circuit current" T which reaches the rectifier E will be insuflicient to effectively energize track R For similar reasons, the failure of any inthrough the associated filtefF.

sulated rail joint will not result in the false energization of the relay for one of the 1 affected sections by track circuit current from the other affected section.

If the railway is of the electric propulsion type and the propulsion current is alternat ing in character, the frequency of the pro pulsion current will be difierentfromreither of the f'requen'cies of the traclr circuit currents. sioncurrenttin the twotrack rails. of any,

of the'a'ssoei'ated track relay bee'a usjethe propulsion current will not be trans1nit ted- It follows that unbalanced'pr'opuli tween the rails of eachsection and the asso ciated rectifier andituned to the frequency of the current fsupplied'to the section, whereby if an insulated rail joint should fail the relay for one of the affected sections will not befalsely operated by track circuit current from the other affected section, and whereby c the relafi ot be falsely operated by P Opulsion current.

In testimony whereof I aflixriny signature.

1 eEoR-enw. BAUGHMAN.

eetien will not result infaifse' energiz'atibn In the event that the propulsion current i is direct, the alternating coinponents of'such current; duefor example to= commutator 1 ripples, Y cannot jcause false energizationi of thetraclrirelays R, because such components i will be different in fr'equency from the he que'ncies; to whichthe filters Fare tuned;

and, consequently; suchzcompon-ents willbe suppressed by; these-filters. Y r

. Although ilhave herein shown and described pnly one form of signaling, system embodying my invention, itis understood V C that various; changes and modifications may i V be made thereinithin the scope of the apv spirit an'dcseope: of invention.

g Having thus described my invention; what V I claim pended claims without departingifrom the 1. In' i c'ombi'nation-,- a stretch of railway track divided injtofl sections-by insulated rail joints, a source o-falternating'traekg "circuit current connected with the rails ofeach'sec tion,1 thefjfrequency of the source for each therailsofeach'sectionand the associated Y rectifier-andl-tune'd to-the frequency of the currentsupplied to thesection, whereby if from' theother affected section; i

I" combination, a stretch of electric railway diy ided into sections by insulated rail joi nts a source of alternatingItra'cl;'cir- I 7' cuitacurrenticonnectedwith: the rails "of: each secti-onethe-if-requency ofrthe sourcet-foi' eacli section' diif ei ing rfromi the: frequency of the V -scurc'es for; each adjacent? section, a rectifier V V V a fen ealchtse'cti'on "receiving"currenfiffro'mftlie I a'ilsof the section," a directfcurrent track a H "relay connecte'd with the outpii'ti tenrn inais; a t

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